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MacBook Pro RAID 0 possible? newbie questions here

K

kkar

macrumors member
Original poster
Apr 6, 2015
49
30
Toronto, Canada
I have the macBook pro 15 in my sig. Can I buy a hdd tray on ebay for the DVD drive and put in another SSD in addition to my current SSD and then run them in RAID 0? Will my motherboard support that? If yes, how do I tell it to run it in raid 0?

If yes, do I have to use the exact same SSD (because it is discontinued) or can any 2 SSDs work? Or do they have to be the same size?
 
Yes, you can do that with your computer though I do question the risk vs. reward of such a move. SSD doesn't have the same latency that hard drives do, so RAID 0 has less of a performance impact but the risk of your data is high since the data is stripped across volumes.

Make sure you have a rock solid backup plan.
 
I understand the risks of running RAID 0. Thanks for your concern.

How do I enable raid 0?

I think the motherboard is only SATA2, so is it worth it to run raid 0?
 
You need to boot up from the recovery partition or the Systems discus (depending on the version of OS X) and run the disk utility, from there you can define and setup the RAID and reinstall the OS and restore the data.
 
Whilst I would normally agree with @maflynn the speed bump for you with 2 ssd's in raid 0 on that machine will mean you getting ssd speed like most users do in later models with one ssd. The obvious reason being your limited to sata2 on both ports. Saturating both will give you close to sata 3 speeds.

But as above cmd-r on boot. Open disk utility and look at the raid tab.
 
1) Is there any point in running a raid setup if i am on Sata2? my current SSD is a sata 3 and it is already bottlenecked by sata2 (i guess) without the raid. what does raiding with another SSD accomplish?

2) My current SSD is discontinued (it is an older model). will getting a current 256gb ssd work fine with the raid?

2a) if i get a different drive, the new drive should be faster, does it matter which drive is the "boot" drive, that is the drive in the proper drive slot, as opposed to the DVD caddy.

3) i read some bits about TRIM and it doens't work with RAID, will it be a issue? I always thought trim was a big deal.

4) what should the block size be, most the info out there on the internet is for HDDs, i am trying to raid 2 SSDs.
 
Gav2k said:
Whilst I would normally agree with @maflynn the speed bump for you with 2 ssd's in raid 0 on that machine will mean you getting ssd speed like most users do in later models with one ssd.
Click to expand...
No arguments there but perhaps I'll go out on a limb and say that very few people actually need that level of performance to get their work done. So while it will improve performance the risk to me seems too high, i.e., risk vs. reward is skewed to much on the risk side.

Perhaps the risk is less so, given the stability of today's SSDs as compared to hard drives but I think noting the risks needed to be said so the OP can make an informed decision.
 
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maflynn said:
No arguments there but perhaps I'll go out on a limb and say that very few people actually need that level of performance to get their work done. So while it will improve performance the risk to me seems too high, i.e., risk vs. reward is skewed to much on the risk side.

Perhaps the risk is less so, given the stability of today's SSDs as compared to hard drives but I think noting the risks needed to be said so the OP can make an informed decision.
Click to expand...
Defiantly agree with you on that side of things and the op should do full backups to help with this. Drive failures do happen and increasing that risk in raid 0 isn't worth it for some.
 
kkar said:
1) Is there any point in running a raid setup if i am on Sata2? my current SSD is a sata 3 and it is already bottlenecked by sata2 (i guess) without the raid. what does raiding with another SSD accomplish?

2) My current SSD is discontinued (it is an older model). will getting a current 256gb ssd work fine with the raid?

2a) if i get a different drive, the new drive should be faster, does it matter which drive is the "boot" drive, that is the drive in the proper drive slot, as opposed to the DVD caddy.

3) i read some bits about TRIM and it doens't work with RAID, will it be a issue? I always thought trim was a big deal.

4) what should the block size be, most the info out there on the internet is for HDDs, i am trying to raid 2 SSDs.
Click to expand...

I think you need to do some actual reading on RAID.

1) you will have 2 SATA 2 busses feeding the system

2) Never mix drives particularly when striping

2a) there is not single boot drive when RAIDing disks the OS sees it as one big disk (Excluding JBOD)

3) TRIM might or might not work but I wouldn't use it

4) block size you can do some math with you're drives and commonly used file sizes.
 
if i add an HDD to replace my DVD drive and go with RAID 1 instead of RAID 0, will I have to erase all my data on the main SSD Drive? or it is drop it in and that's that?
 
kkar said:
if i add an HDD to replace my DVD drive and go with RAID 1 instead of RAID 0, will I have to erase all my data on the main SSD Drive? or it is drop it in and that's that?
Click to expand...
Make a time machine backup. Install 2 identical drives in the optical bay and regular bay then boot via Cmd+R into your Time Machine backup then use Disk Utility to make a Raid 1 and restore your system.
 
kkar said:
if i add an HDD to replace my DVD drive and go with RAID 1 instead of RAID 0, will I have to erase all my data on the main SSD Drive? or it is drop it in and that's that?
Click to expand...

Let me see if I can answer your question. Initial setup on RAID 1 will be that both hard drives need to be configured at the same time. Which means they both will be initially erased and configured for RAID 1. Once that is done, you can start using the hard drives. Later on, if you replace one of the hard drives, the new hard drive will be rebuilt. During the rebuild the RAID 1 is still usable, meaning you can still read and write to the RAID 1 while it is rebuilding.

Something you could do, is clone your internal hard drive before you setup RAID 1 and clone it back to the RAID 1. This would require a third hard drive.
 
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TheIguana said:
Yes you will.

Unless you have matching drives going with either RAID 0 or 1 is a terrible idea.
Click to expand...

You didn't answer the question, thanks for your useless reply, I mean it.

Taz Mangus said:
Let me see if I can answer your question. Initial setup on RAID 1 will be that both hard drives need to be configured at the same time. Which means they both will be initially erased and configured for RAID 1. Once that is done, you can start using the hard drives. Later on, if you replace one of the hard drives, the new hard drive will be rebuilt. During the rebuild the RAID 1 is still usable, meaning you can still read and write to the RAID 1 while it is rebuilding.

Sonothing you could do, is clone your internal hard drive before you setup RAID 1 and clone it back to the RAID 1. This would require a third hard drive.
Click to expand...

Thank you for answering the question. Your reply was great.
 
Taz Mangus said:
Modern RAID 1 does not require matching hard drives.
Click to expand...

You are asking for trouble... In any case if the OP goes down this route they should have a darn good backup of any data on the setup.

Edit: Scratch that I'm still thinking RAID 0 for some reason. :/ Matched pair is more important for RAID 0 for reliability. You are correct RAID 1 works fine with non-matched drives although the smaller drive defines the max capacity.
 
Last edited:
kkar said:
Thank you for answering the question. Your reply was great.
Click to expand...

I have tried using the native RAID 1 in OS X and could not get it to work properly. And what I mean by not working properly, OS X would determine that it needed to rebuild the RAID 1 for no good reason that I could detect. Because of this I decided to go with SoftRaid. SoftRaid has been rock solid. It does cost $179. Maybe in 10.11 native RAID 1 has been improved.
 
TheIguana said:
You are asking for trouble... In any case if the OP goes down this route they should have a darn good backup of any data on the setup.

Edit: Scratch that I'm still thinking RAID 0 for some reason. :/ Matched pair is more important for RAID 0 for reliability. You are correct RAID 1 works fine with non-matched drives although the smaller drive defines the max capacity.
Click to expand...

Not sure that I would use a RAID 1 internally. Requires extra work getting to the hard drives if needed. I can see a reason though, not having to carry around an extra hard drive to do a backup.
 
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